The invention is particularly well suited for use in a rotary F coupler as described, for example, in U.S. Pat. No. 2,990,963 which describes a rotary connector which has a ledge for supporting the pin used to fasten the coupler to the connector that is rotatable within the yoke of the draft gear which is secured to the underside of a railroad car body. The provision of such ledges reduces the bearing area between the pin and rotary connector, especially if the ledge is made sufficiently thick to withstand the stresses imposed upon it by the pin. It has been found that a good thick ledge critically reduces the bearing area of the rotary connector and a ledge of insufficient thickness causes the rotary connector to fracture and break in this area. The invention is directed to improving the bearing between the pin and rotary connector without critically reducing the thickness of the ledge used in supporting the pin within the connector.
Briefly stated, the invention is in a rotary railroad car coupler that comprises a coupler head and a shank which extends from the head and terminates at a butt end in which is located a pinhole that extends transversely through the shank. The butt end of the coupler shank is pinned within a rotary connector that is provided with a pair of opposing sides which have aligned openings that are, in turn, aligned with the pinhole in the coupler shank when the butt end of the shank is properly inserted within the rotary connector. The opening in one of the opposing sides of the rotary connector is restricted by at least two opposing abutments. The pin that is used to couple the butt end of the coupler shank to the rotary connector, is formed from at least two cylindrical pin portions of different diameters that fit within and span the pair of aligned openings in the rotary connector. An annular stop is formed between the two pin portions and is designed to rest against the two opposing abutments of the rotary connector, when the pin is properly inserted so that the pin is generally coextensive with the pinhole of the shank and the aligned openings in the rotary connector.
The use of a pivot pin with different diameters permits the optimization of the pin length without sacrificing the thickness of the ledges used to support the pin within the rotary connector.